Rate

> 250 (uncountable)

Regularity

Irregular (unidentifiable)

P waves

None

PRI

None

QRS

Chaotic

Rate

Any

Regularity

Irregular pattern, but regular R-R

P waves

Upright and uniform

PRI

No relationship between P and QRS

QRS

May be narrow or wide

Rate

60-100

Regularity

Irregular

P waves

Upright and uniform

PRI

0.12-0.20

QRS

0.08-0.12